1. Field of the Invention
This invention concerns slate roofing material joints and the structure of slate roofs using such slate roofing material joints as slate roof tiling technology.
2. Prior Art
Description of the Related Art
When tiling roofs using flat slate roofing tiles as roofing, the work was done as shown in conventional FIG. 6.
That is to say, the flat roofing tiles 52 were installed with two-thirds of the pieces of roofing material overlapping in the direction of the slope on top of the waterproof sheet 51 laid on the roof backing 50. As can be seen from the sectional view given in the figure, with that structure three flat slate roofing tiles 52, always overlap in the cross-sectional direction on completion of the tiling.
With the conventional slate roof tiling structure mentioned above, the intention is to prevent leakage with a structure of multiple overlapping of flat slate roofing tiles with considerable overlapping. However, that structure cannot be used on roofs with a gentle slope of 35/100 or less.
Furthermore, with the trend in recent years to use higher-class roofing, tiling is now being done with natural slate roofing making use of "genshooseki", and as a result there is not only a slope problem but also the problem of strengthening the supporting roof structure because of the greater load per unit of surface area due to the weight of the "genshooseki". The weight problem is significant especially if the conventional 3-tile overlap structure is used.
In addition, with the conventional 3-tile overlap structure there is the problem of the high cost roofing because of the large number of tiles that have to be used as a result of the considerable overlapping.